1. Field of the Invention
The present invention relates generally to vehicle bunks and, more particularly, to a dynamically leveled bunk for use on a truck.
2. Description of the Problem
Extended cab trucks afford room for a bunk behind the operator""s seat allowing the driver a place to sleep when on break. Patents directed to such bunks have focused on providing motion damping for the bunk making the bunk more comfortable for a relief driver while the truck remains in motion. Examples of the such patents include U.S. Pat. No. 4,713,851 to Rosquist; U.S. Pat. No. 4,868,939 to Tagtow; and U.S. Pat. No. 6,493,886 to Vanpage et al. The Vanpage reference provides a mattress suspension including a support device attached between a lower frame attached to the cab floor and an upper frame which carries the mattress. The support device is described as an air sleeve or air cushion capable of providing an upward force to the upper frame. Air is supplied through a fluid connection to the vehicle""s air system. The amount of air in the support device is user controlled.
While the art cited above attempts to deal with road shock and noise encountered by a moving vehicle, this art does not address the discomfort and disorientation experienced by operators attempting to sleep on a non-level mattress. The extensive under bed support arrangements taught by the prior art also compromise use of the space under the bunk mattress for internal storage.
According to the invention there is provided a bunk assembly having pneumatic supports distributed around the perimeter of a platform which support a mattress. The pneumatic supports provide full two axes leveling of the platform and mattress. Deviation of the mattress from the horizontal is detected by first and second level sensors mounted with respect to the platform in the plane of the platform. Different extensions of the supports are adjusted using vehicle compressed air. Control is automatic and is implemented using microcontroller technology. The leveling algorithms executed by the microcontroller filter and the level sensor input slow changes in orientation.
Additional effects, features and advantages will be apparent in the written description that follows.